| Co-Investigator(Kenkyū-buntansha) |
ITO Hiroshi Tokyo Institute of Technology, Department of Organic and Polymeric Materials, Research Associate, 大学院・理工学研究科, 助手 (20259807)
SHIOYA Masatoshi Tokyo Institute of Technology, Department of Organic and Polymeric Materials, Associate Professor, 大学院・理工学研究科, 助教授 (10196363)
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| Research Abstract |
High-speed melt spinning of polylactides with various D-lactide contents was carried out and the structure and properties of the as-spun fibers were investigated. The highest take-up velocities attained for polylactieds with low, middle and high D-lactide contents (PLA-L, PLA-M, and PLA-H) ware 10, 9, and 8 km/mm, respectively. Birefringence of as-spun fibers increased with an increase in the take-up velocity. Fiber obtained at high take-up velocities showed lower birefringence with increasing the D-lactide contents. Distinct crystalline reflections appeared in WAXD patterns of PLA-L and PLA-M fibers spun at 5 and 6 km/min and higher, respectively. The crystal modification was a-form. In DSC thermograms, because of the difference in crystallinity of polymers and the effect of molecular orientation on crystallization rate, cold crystallization was observed for the PLA-L fibers obtained in a low take-up velocity region, whereas in a high take-up velocity region it was observed for PLA-M
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fibers. Crystallinity analyzed from DSC thermograms of PLA-L and PLA-M increased with an increase in the take-up velocity. PLA-L fibers showed significantly higher crystallinity than PLA-M fibers, whereas PLA-H fibers were found to be amorphous up to the highest take-up velocities attained. Mechanical properties of as-spun fibers increased with increasing take-up velocities. The highest initial Young's modulus and tenacity, which were PLA-L fibers obtained at 10 km/min, were about 5.9 Gpa and 570 Mpa, respectively. High-speed melt spinning of polylactides with various D-lactide contents was carried out and the structure and properties of the as-spun fibers were investigated. The highest take-up velocities attained for polylactieds with low, middle and high D-lactide contents (PLA-L, PLA-M, and PLA-H) ware 10, 9, and 8 km/mm, respectively. Birefringence of as-spun fibers increased with an increase in the take-up velocity. Fiber obtained at high take-up velocities showed lower birefringence with increasing the D-lactide contents. Distinct crystalline reflections appeared in WAXD patterns of PLA-L and PLA-M fibers spun at 5 and 6 km/min and higher, respectively. The crystal modification was a-form. In DSC thermograms, because of the difference in crystallinity of polymers and the effect of molecular orientation on crystallization rate, cold crystallization was observed for the PLA-L fibers obtained in a low take-up velocity region, whereas in a high take-up velocity region it was observed for PLA-M fibers. Crystallinity analyzed from DSC thermograms of PLA-L and PLA-M increased with an increase in the take-up velocity. PLA-L fibers showed significantly higher crystallinity than PLA-M fibers, whereas PLA-H fibers were found to be amorphous up to the highest take-up velocities attained. Mechanical properties of as-spun fibers increased with increasing take-up velocities. The highest initial Young's modulus and tenacity, which were PLA-L fibers obtained at 10 km/min, were about 5.9 Gpa and 570 Mpa, respectively. Less
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